OPC UA Client

The OPC UA Client origin
processes data from an OPC UA server. The OPC UA Client origin can poll the server at
regular intervals, returning the latest data from all specified nodes. Or it can
subscribe to specific nodes and receive messages from the server each time a change
related to a specified node occurs.

The origin can also browse all available nodes to provide the node details that you need
to configure the origin.

When you configure the OPC UA Client origin, you specify connection information and tag
information to associate with each client request. You select the processing mode for
the origin and specify the NodeIds for the nodes you want to use. You can use one of
several different methods to provide the NodeIds.

You can configure channel properties, such as the maximum chunk or message size. You can
optionally configure the security policy that you want to use, related TLS properties,
and an optional client private key alias.

Processing Mode

The OPC UA Client origin
processes data differently depending on the mode that you choose. The origin can use the
following processing modes:

Polling

The origin polls the OPC UA server at regular user-defined intervals,
returning the current status of every specified node.

In polling mode, each record contains data from each specified node as a
field. As soon as the origin generates a record, it passes the record to the
pipeline to avoid delays in processing.

For example, say you set the OPC UA Client to poll the server every minute,
and you specify five NodeIds. When the pipeline runs, the origin generates a
record every minute, with the status of each of the five NodeIds in each
record, regardless of whether any changes occurred since the last poll.

Subscribe

The origin subscribes to the specified nodes. The OPC UA server sends an
update each time a change occurs with one of the specified nodes. When node
changes occur, the server sends each change to the origin separately.

In subscribe mode, each record contains a single node change. As soon as the
origin generates a record, it passes the record to the pipeline to avoid
delays in processing.

For example, say you set the OPC UA Client origin to subscribe to ten nodes.
After you start the pipeline, the pipeline sits idly until the OPC UA server
sends data about a change to a subscribed node.

Browse nodes

Browse nodes mode is a tool to aid pipeline development. In browse nodes
mode, the origin connects to the OPC UA server to retrieve all available
node details, such as the node identifier and namespace index.

This mode provides easy access to the node details that you need to
configure the NodeIds in the origin.

You can use browse nodes mode in data preview to view node details and then
configure the origin. Or, you can run a pipeline in browse nodes mode to
write node details to a file. You can alternatively use external methods to
retrieve node details from the OPC UA server.

You can then use this
information to configure the nodes that you want to subscribe to, as
follows:

Providing NodeIds

The OPC UA
Client origin provides several ways to specify the nodeIds for the nodes that you want
to use:

Manual

Manually enter the NodeId information. Use this method when you have a
specific set and low volume of nodes that you want to use. You can use
simple or bulk edit mode.

File

Provide a file of NodeId information. Use this method when you have a
relatively static set of nodes that you want to use. You can update the file
as needed, but will need to restart the pipeline to capture the latest
nodes.

The file must be in a directory local to Data Collector. By default, the origin expects you to secure the information in a runtime resource file.

Enter the NodeId information in the file using the following JSON
format:

Tip: This is the same format used when entering node information
manually in bulk edit mode. To verify the format, you can enter two
NodeIds manually in simple format, then switch to bulk edit mode.

Browse Nodes

Specify a root NodeId, allowing the origin to browse for all available nodes
under the root node. Use this method when you want to process data from a
dynamic set of nodes that are under a single root node.

When you browse nodes, you specify an refresh interval. The refresh interval
indicates how long the origin should wait before browsing again for an
updated list of nodes to process.

Security

You can optionally configure the OPC UA Client origin to use one of the following standard OPC
UA security policies:

Configuring an OPC UA Client Origin

In the Properties panel, on the General tab, configure the
following properties:

General Property

Description

Name

Stage name.

Description

Optional description.

On Record Error

Error record handling for the stage:

Discard - Discards the record.

Send to Error - Sends the record to the pipeline for
error handling.

Stop Pipeline - Stops the pipeline.

On the OPC UA tab, configure the following
properties:

OPC UA Property

Description

Resource URL

OPC UA resource URL to use.

Application Name

Application name to use for contact with the OPC UA
server. This name can appear in reporting tools to identify
the application that sent a request.

Application URI

Application URI to use for contact with the OPC UA
server. Enter a unique ID that begins with "urn" as
follows:

urn:<application URI>

This
name can appear in reporting tools to identify the
application that sent a request.

Request Timeout

Milliseconds to wait for a response before timing
out.

Processing Mode

Mode to use to retrieve data from the OPC UA server:

Polling - Use to request data at regular
intervals.

Subscribe - Use to receive data only when changes
occur for subscribed nodes.

Browse Nodes - Use during pipeline development to
provide node details for configuring Node IDs. Do
not use in production.

For more information about mode types and the data
returned in each mode, see Processing Mode.

Polling Interval (ms)

Milliseconds to wait between polling. Used with the
polling mode only.

On the NodeIds tab, select the NodeId Fetch
Mode.

For more information about the different ways you can provide node
information, see Providing NodeIds.

When using the Manual mode, use simple or bulk edit mode to enter the nodes that you want to use.
Click the Add icon to add additional nodes.

Node Property

Description

Field Name

The name of the node.

Identifier

The identifier for the node within the OPC UA Server
address space.

Identifier Type

The format and data type of the identifier. Use one of
the following types:

Numeric

String

UUID

Opaque

Namespace Index

The index that the OPC UA Server uses for a namespace
URI.

When using the File mode, configure the following property:

File Property

Description

NodeId File Path

Path to the file that contains NodeId information for the
nodes that you want to process. Use a file local to Data Collector that includes the NodeId information in the appropriate
format. For more information, see Providing NodeIds.

Default is
${runtime:loadResource('nodeIdConfigs.json',
false)}, which assumes you are using a
runtime resource file named
nodeIdConfigs.json.

When using Browse mode, configure the following properties:

Browse Property

Description

Root Node Identifier

The identifier for the root node within the OPC UA Server
address space. The origin processes data from all nodes
under the root node.